The role of ternary complexes of enzyme, coenzyme and substrate or substrate analogue as intermediates in the overall reaction mechanism and control of pyridine nucleotide dependent dehydrogenases is being investigated. Substrates which are also inhibitors, such as the N-alkyl substituted aminoethanols will be used to study the abortive complex formation of enzyme, coenzyme (NADH) and ethanolamine derivative, with the horse liver alcohol dehydrogenase system. Amides will also be studied with enzyme and NAD. Studies with purified isoenzymes of lactate and sorbitol dehydrogenase in the reproductive process will permit relation of the ternary complex of enzyme, NAD and pyruvate as a control device wherby a reaction can be directed towards pyruvate oxidation or reduction. The reproductive process will also be studied with the use of antibodies of a number of sperm and testis specific dehydrogenases.